HIMA HIMax X-DO 12 01, Manual, Page: 12 / 52

3 Product Description X-DO 12 01
Page 12 of 52 HI 801 023 E Rev. 5.00
3.4 Structure
The module is equipped with 12 relay outputs. Each relay output is switched by two contacts in
series. After every cycle, the module reads the status of the forcibly guided contacts and
compares it status with the output variables.
The relays in use have forcibly guided contacts (EN 50205) and can be used for safety
shutdowns. Forcibly guided contacts are connected with one another mechanically such that the
normally open and the normally closed contacts cannot be closed simultaneously.
All 12 relay outputs are electrically safely isolated from one another. Each relay output is safely
isolated from the voltage supply of the module by its own contact circuit. For safe insulation, the
air and creeping distances are designed in accordance with IEC 61131-2 for overvoltage class II
up to 300 V.
For burner management systems, the switching current must be limited to 60 % of the maximum
allowed value using an external fuse in accordance with EN 298 and EN 50256 (VDE 0116).
At least two monitored relays must be used to shut down the entire fuel supply safely. HIMA
recommends performing the wiring such as specified in Chapter 4.4.3.
WARNING
Electric shock, damage to module!
The module is not designed for connecting three-phase current!
Only one phase can be connected to the X-DO 12 01 module. Connecting three-phase
current is not permitted!
The safety-related 1oo2 processor system for the I/O module controls and monitors the I/O
level. The data and states of the I/O module are made available to the processor modules via
the redundant system bus. The system bus has a redundant structure for reasons of availability.
Redundancy is only ensured if both system bus modules are inserted in the base plates and
configured in SILworX.
The module is equipped with LEDs to indicate the status of the relay outputs, see Chapter 3.4.2.
The module measures current on each channel (see Chapter 3.5.1) and issues a warning if the
number of switching operations per channel exceeds 250 000.